Do you wonder how many watts a LED lamp needs to light a room properly? Start with the amount of light you are looking for. Watt indicates the electrical power; lumen describes the light output. A LED lamp with fewer watts can still provide as much light as a less efficient lamp.
How many watts does an LED bulb have?
This varies depending on the model. A small decorative lamp requires a different power than lighting for a large work area. Two LED lights with a similar light output can also have a different wattage.
Therefore, there is no fixed conversion that would replace, for example, every 60-watt incandescent bulb with exactly 6 watts of LED. Compare LED lamps first on lumen and then on the power that is required for that.
Which lumen value replaces an incandescent bulb?
The values below provide a practical indication for replacing conventional incandescent bulbs. You should look for the appropriate LED lamp based on its light output, not on a pre-selected LED wattage.
| Old light bulb | Direct value LED light output |
|---|---|
| 25 watts | 200–300 lumens |
| 40 watts | 400–500 lumens |
| 60 watts | 700–850 lumens |
| 75 watts | 900–1100 lumens |
An LED light with an output of about 800 lumens can therefore serve as a replacement for a conventional 60-watt incandescent bulb. In addition, when using a spotlight, you need to compare the beam: the same amount of light can be spread out or directed onto a small area.
Example: two LED lamps of 800 lumens
Suppose two fictitious lamps both provide 800 lumens. Lamp A uses 6 watts and lamp B 8 watts. Lamp A provides approximately 133 lumens per watt; lamp B 100 lumens per watt. For the same total luminous flux, A requires less electrical power in this example.
That doesn’t make A the best choice for every location. Also compare the bundle, color rendering, dimming, dimensions, and permitted use. A more economical lamp that doesn’t fit into the fixture or has the wrong light distribution won’t solve your lighting problem.
With five hours of fire per day, A consumes approximately 10.95 kWh annually and B 14.60 kWh. The difference is 3.65 kWh per year. These are energy amounts in kWh. The calculation assumes the stated power during fires as constant and does not take into account any standby consumption.
Watt is power, kWh is energy consumption
An 8-watt light bulb uses 8 watt-hours when lit for one hour, or 0.008 kWh. When lit for five hours, that is 0.04 kWh. This calculation example assumes a constant power of 8 watts during the burning process.
If you want to know the costs, multiply the consumption in kWh by your electricity price per kWh. The more detailed examples are listed below. how much a lamp costs per hour. This keeps the choice of a lamp and the calculation of the operating costs clearly separate from each other.
Why lumen does not describe the entire light spectrum
Two lamps with the same number of lumens can produce a different result. The beam angle, distance from the illuminated surface, and the fixture all affect where the light falls. Moreover, a dark lamp shade blocks part of the light.
Therefore, look at the light distribution when choosing spots. Read How to choose a GU10 bulb or use the explanation about lumen per space for a broader lighting plan.
When does wattage remain important?
The actual wattage counts towards the maximum lamp power of a fixture and the load of a dimmer. Do not use the ‘replaces 60 watts’ designation when doing so. That is a comparison with another light source.
With a standalone driver or led strip, just having enough wattage isn’t enough. Voltage, power control, dimming method, and other connection requirements must also be compatible. Have that combination checked using the product specifications.
This is how you choose a suitable LED light bulb
- Decide which surface or object you want to illuminate.
- Compare the lumen and, for spotlights, the beam angle.
- Choose a suitable light color; more Kelvin does not automatically mean more light.
- Check the fitting, dimensions, voltage and permitted use.
- Check the actual power and check for any dimming.
If you want to replace an existing light source, then follow the steps below. Replacing a LED light.
